These pipe caps are available in a range of national pipe thread (NPT) sizes:

1/8"

1/4"

3/8"

1/2"

3/4"

Measuring pipe: Remember all pipe is measured from the inside diameter of the male pipe. This means that a Female pipe fitting that is labelled as 3/4 is large enough to screw onto a Male pipe fitting that has an inside pipe diameter of 3/4"